1. Technical Field
The present invention relates to an image photographing device having a function for compensating for hand vibration, and more particularly, to an image photographing device having a function for compensating for hand vibration in which coils and magnets are additionally disposed outside a bobbin having a lens unit mounted therein to simultaneously perform auto focusing and hand vibration compensation.
2. Description of the Related Art
Recently, the use of a subminiature camera has gradually increased in a mobile device such as a cellular phone, a notebook, a tablet PC, or the like. The demand of customers for subminiature camera used in the mobile device and having a high pixel of five million pixels or more and a multi-function such as a zoom function, an auto focus (AF) function, and the like has been increased.
Generally, a camera module used in the mobile device may be configured to include an optical system having a lens, a lens driver moving the optical system in an optical axis direction to adjust a focus, and an image sensor photographing light input through the optical system to convert the photographed light into an image signal.
As the number of pixels of the camera module is increased and the function thereof is diversified, the size of the pixel becomes small and the number of components through which the light passes is increased. Accordingly, the receiving sensitivity of the light photographed by the image sensor becomes sensitive, and the image photographed by the image sensor becomes out of focus even with small hand vibration when operating a shutter of the camera or the mobile device, such that image quality is deteriorated. Therefore, it is impossible to obtain a sharp photograph.
The light passing through the lens of the optical system becomes out of the optical axis of the lens due to the hand vibration. Therefore, in order to prevent the deterioration of the image quality due to the hand vibration, the lens is moved in a direction perpendicular to the optical axis to coincide the optical axis of the lens with an incident path of the light or the image sensor is moved in a direction perpendicular to the optical axis to align the optical axis with an incident path of the light received in the image sensor, thereby compensating for the hand vibration.
That is, the lens or the image sensor is relatively displaced in the direction perpendicular to the optical axis, respectively, thereby making it possible to compensate for the hand vibration.
In a scheme that relatively displaces the lens or the image sensor to compensate for the hand vibration, generally, a two-axis guide supporting the lens in a T shape or an L shape is mounted, such that the lens is moved in the relative direction of the driving displacement generated due to the hand vibration, while being moved in the direction perpendicular to the optical axis along the two-axis guide, thereby compensating for the hand vibration.
When the lens is moved along the two-axis guide, a compensation performance may be deteriorated due to the friction between the two-axis guide and the lens. Also, when driving the two-axis guide and the lens or the two-axis guide, noise or foreign material may occur due to the friction with other components.
In addition, since the two-axis guide supports the periphery of the lens, the size of the camera module cannot but be enlarged by a space in which the two-axis guide is mounted.